Ink Compositions

ABSTRACT

A heat exchanger for an electrical element is provided. The heat exchanger includes a first plate, a second plate adapted to contact the electrical element and a plurality of heat exchange channels. The plurality of heat exchange is between the first and second plates to enable heat exchange between a fluid flowing in the plurality of heat exchange channels and the electrical element. The heat exchanger further includes a first portion and a second portion. The first portion of the heat exchange channels is in thermal contact with a first of the electrical elements and the second portion of the heat exchange channels is in thermal contact with a second of the electrical elements. Further, the first portion has an area different from the area of the second portion

The present invention is relates to a heat exchanger, more particularlyto a heat exchanger for an electrical element, particularly batter pack,to maintain homogenous temperature amongst the electrical element.

Generally, battery packs are provided in automobiles to supply power tovarious elements of the automobiles. While charging or dischargingbatteries provided in the battery packs, heat may be generated, whichneeds to controlled or reduced to have efficient charging anddischarging of the batteries. Further, the temperature of the batterypacks is to be maintained to increase service life of the battery pack.

To maintain the temperature of the battery pack at an optimum level, aheat exchanger can be provided on the battery pack, which exchanges heatgenerated in the battery pack with a coolant flowing through the heatexchanger to dissipate the heat generated in the battery pack. Further,the conventional heat exchanger may have uniform cooling channelsthroughout the heat exchanger, so the coolant entering into an inlet ofthe heat exchanger is colder than of the coolant flowing in the rest ofheat exchanger. Hence, the conventional heat exchanger may causedifferent level of heat exchange between heat generated by battery cellsand the coolant across the battery pack. As the heat exchanger providedwith the battery pack may have uniform contact surface, uneven heatexchange may occur across the battery pack. Thereby, the battery packmay have different temperature at different regions of the battery pack,which results ineffective performance of the battery pack. Further,ineffective cooling of batteries may reduce service life of the batterypack.

Accordingly, there remains a need for a heat exchanger that maintainshomogenous temperature across a battery pack. Further, there remains aneed for heat exchanger that increase service life of the battery pack.

In the present description, some elements or parameters may be indexed,such as a first element and a second element. In this case, unlessstated otherwise, this indexation is only meant to differentiate andname elements, which are similar but not identical. No idea of priorityshould be inferred from such indexation, as these terms may be switchedwithout betraying the invention. Additionally, this indexation does notimply any order in mounting or use of the elements of the invention.

In view of the foregoing, an embodiment of the invention herein providesa heat exchanger for an electrical element. The heat exchanger includesa first plate, a second plate adapted to be thermally coupled with theelectrical element, and a plurality of heat exchange channels. Theplurality of heat exchange is defined between the first plate and thesecond plate to enable heat exchange between a fluid flowing in theplurality of heat exchange channels and the electrical element. The heatexchanger further includes a first portion and a second portion. Thefirst portion of the heat exchange channels is in thermal contact with afirst of the electrical elements and the second portion of the heatexchange channels is in thermal contact with a second of the electricalelements. Further, the first portion has an area different from the areaof the second portion.

In one embodiment, wherein the first portion of the channels hasvariable cross-section and the second portion of the channels hasconstant cross-section. In another embodiment, the heat exchanger mayinclude a third portion of channels having variable cross-section.

In one embodiment, the area of fluid contact surface in the firstportion of the plurality of heat exchange channels to the electricalelement is 3-20%, preferably 5 to 15%, smaller than the area of fluidcontact surface in the second portion of the plurality of heat exchangechannels to the electrical element.

In one example, the first plate comprising a second plate part and afirst plate part having depressions that form the plurality of heatexchange channels.

In another example, the second plate comprises a first plate part and asecond plate part, wherein the first plate parts of the first and secondplates are spaced apart forming the plurality of heat exchange channels,and wherein the second plate parts of the first and second plates arebound together in a liquid tight manner.

Further, the second plate is in contact with the first plate to form thedepression provided in the first plate as closed channels.

In yet another embodiment, the plurality of heat exchange channels isbranched out, along the flow direction, as a tree from the first portionof the plurality of heat exchange channels.

In one aspect, the plurality of heat exchange channels is a U-shapedchannel. Further, an inlet and an outlet are formed on one side of theheat exchanger.

In another aspect, the plurality of heat exchange channels is anI-shaped channel. Further, an inlet and an outlet are formed on oppositesides of the heat exchanger respectively.

In another aspect of the invention, a thermal system is provided. Thethermal system includes a heat exchanger and an electrical element.Further, the electrical element is formed as multiple sets of batteryspaced apart from each other and the electrical element is placed belowand in thermal interaction with the first plate.

Further, the first portion of the plurality of heat exchange channels isadapted to be in contact with a first set of cells of the electricalelement and the second portion of the plurality of heat exchangechannels is adapted to be in contact with a second set of cells of theelectrical element.

In another embodiment, a ratio between the first plate part and a secondplate part in the first portion (108) of the plurality of heat exchangechannels is smaller than

a ratio between the first plate part and a second plate part in thesecond portion of the plurality of heat exchange channels, is a range of80% to 97%, preferably 95% to 85%, advantageously around 90%.

Other characteristics, details and advantages of the invention can beinferred from the description of the invention hereunder. A morecomplete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying figures, wherein:

FIG. 1A illustrates a schematic representation of the heat exchanger, inaccordance with an embodiment of the present invention;

FIGS. 1B and 1C illustrate exploded views of the heat exchanger of FIG.1A without and with the battery pack respectively;

FIG. 2 illustrates a cross-sectional view of the heat exchanger of FIG.1A provided with a second plate; and

FIGS. 3A-C illustrate top views of channels of the heat exchanger ofFIG. 1A, showing area of fluid contact surface of the channels atdifferent sections along the length of the channels.

It must be noted that the figures disclose the invention in a detailedenough way to be implemented, the figures helping to better define theinvention if needs be. The invention should however not be limited tothe embodiment disclosed in the description.

The present invention relates to a heat exchanger for a battery packhaving one or cells. The one or more cells are grouped together to formthe battery pack. The batter pack may provide energy to electricalcomponents of a vehicle. As the battery pack is main source forproviding energy to the electrical components of the vehicle, thebattery pack may get heated and temperature of the battery pack needs tobe maintained at an optimum level for efficient performance of thecells. Further, the one or more cells in the battery pack may releasedifferent amount of heat and as such are at different temperatures, so aheat exchanger connected to the battery pack for cooling of the cells,should be able to uniformly cool the battery pack, so that the averagetemperature of the one or more cells are same. If cooling of the batterypack is uneven across the battery pack, attaining homogenous temperatureacross the battery pack is cumbersome. To achieve homogenous coolantflow rate across the heat exchanger, the heat exchanger is provided withnon-identical coolant-contact surface between the heat exchanger and thebatter pack. As the coolant flow rate in the heat exchanger isnon-identical across the heat exchanger, the heat exchanger can cool thebattery pack according to heat level released from corresponding cellsof the battery pack, thereby attaining homogenous temperature across thebattery pack.

While aspects relating to a heat exchanger having non-identicalcoolant-contact surface across the heat exchanger for a battery pack asdescribed above and henceforth can be implemented for any other deviceshas heterogeneous temperature level across the devices to cool thedevice, the embodiments are described in the context of the followingsystem(s).

FIGS. 1A, 1B and 1C illustrate different views of a heat exchanger 100for an electrical element 102, in accordance with an embodiment of thepresent invention. The electrical element 102 provides energy to anyelectrical components and emits heat while power the electricalcomponents. In one example, FIG. 1A illustrates a schematic view of theheat exchanger 100, and FIGS. 1B and 1C illustrate exploded views of theheat exchanger 100 without and with the electrical element 102. Theelectrical element 102 is a collection of cells serially arrangedtogether, in a vehicle for providing electrical energy to the variouscomponents in the vehicle. The electrical element 102 may be providedin-contact with the heat exchanger 100 in order to enable heat exchangebetween the heat generated in the electrical element 102 and a coolantflowing in the heat exchanger 100. In one embodiment, the electricalelement 102 may include the cells 102A, 102B arranged serially andadapted to charge/discharge according to the requirements. Whilecharging or discharging of the cells 102A, 102B in the electricalelement 102, the cells may release heat, which is undesirable. Further,the coolant flowing into the heat exchanger 100 may have different heatexchange capability at different location, since the temperature of thecoolant is not same throughout the heat exchanger 100. For example, thecoolant entering through an inlet of the heat exchanger 100 is havingless temperature level than of the coolant flowing at the body of theheat exchanger 100. Whereas, the coolant coming out from an outlet ofthe heat exchanger 100 is having highest temperature than of the body ofthe heat exchanger 100. Therefore, the heat exchange between the heatgenerated by the electrical element 102 and the coolant flowing in theheat exchanger 100 is non-uniform. Hence, the electrical element 102 mayexperience different temperature levels across the electrical element102. For example, the cells 102A provided in the corners of theelectrical element 102 may be in thermal contact with the coolant havinglowest temperature and highest temperature, than of the coolantthermally contacting the cells 102B provided in the electrical element102. Therefore heterogeneous heat exchange occurs across the electricalelement 102, which reduce the life span of the electrical element. Toavoid such scenario, coolant contact surface across the heat exchangeris modified, so that the inlet area of the heat exchanger 100 and theoutlet area have less flow of coolant than of rest of the heat exchanger100.

In one aspect of the invention, the heat exchanger includes a firstplate 106 and a second plate 112 adapted to be coupled the first plate106. Further, a plurality of heat exchange channels 104 is defined oneither of the first plate 106 or the second plate 112. In oneembodiment, the plurality of channels 104 can be formed partially on thefirst plate 106 and the second plate 112. Further, the plurality of heatexchange channels 104 having different cross-sections are formed in theheat exchanger 100 to enable flow of the coolant in the plurality ofheat exchange channels at different volumes and different flow rates.The plurality of heat exchange channels 104, hereinafter referred to aschannels, can be formed in the first plate 106 of the heat exchanger100. The first plate 106 may include a first plate part 106A havingdepressions and a second plate part 106. In one embodiment, thedepressions formed in the first plate part 106A of the first plate 106may form the channels 104, when the first plate 106 is coupled to thesecond plate 112. The second plate 112 is formed in such a way that thefirst plate 106 is in contact with the electrical element 102. In oneembodiment, the second plate 112 may be in thermal contact to theelectrical element 102, to enable heat exchange between the electricalelement 102 and the coolant flowing in the channels 104 of the heatexchanger 100. In another example, the channels 104 may defined betweenthe first plate 106 and the second plate 112 to enable heat exchangebetween the coolant and the electrical element 102. In another example,the second plate 112 comprises a first plate part 112A, and a secondplate part 1128. Further, the first plate parts 106A, 112A of the first106 and second 112 plates are spaced apart forming the plurality of heatexchange channels, and the second plate parts 1068, 1128 of the first106 and second 112 plates are bound together in a liquid tight manner.

The channels 104 defined in the first plate 106 may classified as afirst portion of channels 108 and a second portion of channels 110. Inone embodiment, the first portion of channels 108 are having less crosssection as comparted to the second portion of channels 110, so that thefirst portion of channels 108 have different flow rate of the coolantfrom that of the second portion of channels 110. In other words, thefirst portion of channels 108 has an area different from the area of thesecond portion of channels 110, preferably first portion of channels 108has less area than of the second portion of channels 110. As the crosssection of the first portion of channels 108 is lesser than of thesecond portion of channels 110, heat exchange between the cells 102Aprovided in the electrical element 102 corresponding to the firstportion of channels 108 and the coolant flowing in the first portion ofchannels 108, is low as compared to second portion of channels 110 ofheat exchanger 100. Further, the coolant flowing in the first portion ofchannels 108, corresponding to the inlet, is colder than of the coolantflowing in the second portion of channels 110. And, the coolant flowingin the first portion of channels 108, corresponding to the outlet ishotter than of the coolant flowing in the second portion of channels110. Therefore, to attain uniform heat exchange between the electricalelement 102 and the heat exchanger 100, smaller cross-section ofchannels in the first portion of channels 108 is optimum than of thecross-section of channels in the second portion of channels 110.Further, the first and second portions of channels 108, 110 are portionsin thermal contact between the channels 104 and electrical elements 102.In other words, the first portion of channels 108 corresponds to the sumof each individual portion of the channels 108-1, 108-2, 108-3 that areseen by the considered electrical element.

Further, the coolant flowing in the second portion of channels 110 iscomparatively warmer than the coolant flowing in the first portion ofchannels 108, so larger cross-section of channels in the second ofportion channels 110 is required to cool the cells 102B provided in theelectrical element 102 to the nominal level. Thereby, the electricalelement 102 is maintained at the nominal temperature throughout all thecells of the electrical element 102.

In one embodiment, the channels 104 are engraved on the first plate 106to form the channels 104 as semi-closed channels. In another embodiment,the channels 104 are formed by creating depression on the first platepart 106A of the first plate 106 as shown in FIG. 2 . Further, thesecond plate 112 is fixed on a side of the first plate 106 on which thedepressions are provided, so that the depression can become as closedchannels. FIG. 2 illustrates a cross-sectional view of the heatexchanger 100 provided with the second plate 112. Further, the secondplate 112 is provided with the first plate 106 in such a way that thechannels/depressions 104 on the first plates 106 and the second plate112 forms closed channels to enable flow of the coolant there through.The second plate 112 may be in thermal contact with the electricalelement 102 to enable heat exchange there-between. Further, the firstportion of channels 108 are formed in such a way that the first portionof channels 108 are merged together to form a single channel. In otherwords, one end of the first portion of channels 108 may merged, along anopposite direction to a flow direction of the coolant, to form as asingle channel. So formed signal channel enable introduction andreception of the coolant to and from the channels, and another end ofthe first portion of channels 108 are connected to the second portion ofchannels 110. The first portion of channels 108 and the second portionof channels 110 are connected together to forms the channels 104, whichenable continuous flow of the coolant in the heat exchanger 100.Further, the heat exchanger 100 and the electrical element 102 arecollectively referred to as a thermal system.

The heat exchanger 100 may include of the at least one inlet 202 adaptedto introduce the coolant to the channels 104 and of the at least oneoutlet 204 adapted to receive the coolant from the channels 104 afterthe coolant had extracted heat from the electrical element 102. Further,the at least one inlet 202 and the at least one outlet 204 are formed onthe first plate 106. According to one aspect of invention, the at leastone inlet 202 and the at least one outlet 204 are connected to the firstportion of channels 108 to enable circulation of the coolant in thechannels 104 of the heat exchanger 100. In such cases, the secondportion of channels 110 are U-shaped channels and connected to the firstportion of channels 108 to form the channels 104. As the first portionof channels 108 and the second portion of channels 110 are connectedtogether, the channels 104 may include two ends such as a first end 206Aand a second end 206B. Further, both the first end 206A and the secondend 206B are in the first portion of channels 108 amongst the channels104, as shown in FIG. 1A. The at least one inlet 202 is connected to thefirst end 206A of the channels 104 and the at least one outlet 204 isconnected to the second end 206B of the channels 104. In such cases, thefirst end 206A and the second 204A of the channels 104 are mergedtogether, along an opposite direction to a flow direction of thecoolant, to form as single channel and connected to the at least oneinlet 202 and the at least one outlets 204 respectively. Hence, the flowrate of the coolant in the first portion of channels 108 amongst theplurality of channels 104 is lower than of the second portion ofchannels 110. As the first portion of channels 108 amongst the channels104 is having less flow rate of the coolant than of the second portionof channels 110, heat exchange in the first portion of channels 108 islesser than of the second portion of channels 110. Further, the channels104 may be branched out, along the flow direction of the coolant, as atree from an inlet amongst the set of inlets 202 in the first portion108 of the plurality of heat exchange channels 104.

According to another aspect of the invention, the set of inlets 202 isconnected to the first portion of channels 108 and the set of outlets204 is connected to the second portion of channels 110. In such case,the second portion of channels 110 is I-shaped channels. Further, theset of inlets 202 may be formed on one end of the first plate 106 andconnected to the first portion of channels 108, and the set of outlet204 may be formed on another end of the first plate 106 and connected tothe second portion of channels 110. The set of inlets 202 may beconnected to conduits carrying the coolant and is adapted to introducethe coolant to the channels 104. As the first portion of channels 108amongst the channels 104 is having less flow rate of the coolant than ofthe second portion of channels 110, heat exchange in the first portionof channels 108 is lesser than of the second portion of channels 110. Asthe cells 102A in the corner of the electrical element 102 emits lessheat than the rest of the cells in the electrical element 102, lesserheat exchange in the first portion of channels 108 than of the secondportion of channels 110 is optimum to maintain average temperatureacross the electrical element 102.

FIGS. 3A-C illustrate top views of the channels 104 of the heatexchanger 100 of FIG. 1A. The channels 104 of the heat exchanger 100 aresuper imposed on the cells 102A of the electrical element 102. The cells102A are serially arranged in rows in the electrical element 102. Therows of cells 102A are evenly spaced from one another in the electricalelement 102 as shown in FIGS. 3A-C. For example, FIG. 3A-C show the topviews of the channels 104 showing coolant-contact surfaces 106C andcoolant non-contact surfaces 106D of the channels 104 with the rows ofcells 102A. In other words, the first plate part 106A is considered asthe coolant-contact surfaces 106C here, and the second plate part 106Bis considered as the coolant non-contact surfaces 106D here. Accordingto the aspect shown in FIGS. 3A-C, the channels 104 illustrated as threesegments, such as a first segment 302 having four rows of cells 102A asshown in FIG. 3A, a second segment 304 having three rows of cells 102Aas shown in FIG. 3B and a third segment 306 having three rows of cells102A as shown in FIG. 3C. Further, the first portion of channels 108 arein the first segment as shown in FIG. 3A, and the second portion ofchannels 110 are shown in the all three segments. Further, the channels104 corresponding to first two rows of cells 102A are having less fluidcontact surface area than of rest of rows of the cells 102A. Further,the heat exchanger 100 can be divided into three zones, namely a firstzone 310, a second zone 312, and a third zone 314. Further, the rows 1-2shown in FIG. 3A are considered as the first zone 310, rows 3-6 shown inFIGS. 3B-C are considered as the second zone 312, rows 7-8 shown in FIG.3C are considered as the third zone 314. In one embodiment,coolant/fluid contact surface in the first zone 310 and the third zone314 is less than of the second zone 312. In this example, the first zone310 includes the first portion of channels 108 and the second and thirdzones 312, 314 include the second portion of channels 110. Further, aratio between the first part plate 106A/coolant-contact surfaces 302 andthe second part plate 106B/coolant non-contact surfaces 304 in the firstzone 310 is 80%. Further, a ratio between the first part plate106A/coolant-contact surfaces 302 and the second part plate 106B/coolantnon-contact surfaces 304 in the second zone 312 is 100%.

As shown above, the first two of cells i.e., row 1 and 2, arecorresponding to the first portion of channels 108 which is having lessfluid area than of the second portion of channels 110. Rest of the rowsof cells i.e., rows 3-8 are corresponding to the second portion ofchannels 110 which is having more fluid area. As the area fluid surfaceis less in the first portion of channels 108 than of the second portionof channels 110, heat exchange between the heat exchanger 100 and theelectrical element 102 is uniform across the electrical element 102. Theheat exchanger 100 cools the electrical element 102 to an averagetemperature across the electrical element 102, irrespective of the cells102A in the electrical element emits heat at different temperature.Therefore, homogenous temperature of the cells in the electrical element102 can be achieved, thereby increasing working life of the electricalelement 102.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that the invention may be practiced otherwise than asspecifically described herein.

In any case, the invention cannot and should not be limited to theembodiments specifically described in this document, as otherembodiments might exist. The invention shall spread to any equivalentmeans and any technically operating combination of means.

1. A heat exchanger (100) for an electrical element (102), comprising: afirst plate (106); a second plate (112) adapted to be in thermallycoupled with the electrical element (102); and a plurality of heatexchange channels (104) defined between the first plate (106) and thesecond plate (112) to enable heat exchange between a fluid flowing inthe plurality of heat exchange channels (104) and the electrical element(102), wherein the heat exchanger comprises: a first portion (108) ofthe plurality of heat exchange channels (102) in thermal contact with afirst of the electrical elements (102) a second portion (110) of theplurality of heat exchange channels (104) in thermal contact with asecond of the electrical elements (102) the first portion has an areadifferent from the area of the second portion.
 2. The heat exchanger(100) as claimed in claim 1, wherein the first portion (108) of thechannels (104) has variable cross-section and the second portion (110)of the channels (104) has constant cross-section.
 3. The heat exchanger(100) as claimed in claim 1, wherein the area of the first portion (108)of the plurality of heat exchange channels (104) is 3-20% lesser thanthe area the second portion (110) of the plurality of heat exchangechannels.
 4. The heat exchanger (100) as claimed in claim 1, wherein thefirst plate (106) comprising a first plate part (106A) and a secondplate part (106B), wherein the first plate part (106A) havingdepressions that form the plurality of heat exchange channels (104). 5.The heat exchanger (100) as claimed in claim 4, wherein the second plate(112) is in contact with the first plate (106) to form the depressionprovided in the first plate (106) as closed channels.
 6. The heatexchanger (100) as claimed in any of the preceding claims, wherein theplurality of heat exchange channels (104) is branched out, along theflow direction of the fluid, as a tree from the first portion (108) ofthe plurality of heat exchange channels (104).
 7. The heat exchanger(100) as claimed in claim 1, wherein the plurality of heat exchangechannels (104) is a U-shaped channel.
 8. The heat exchanger (100) asclaimed in claim 7, further an inlet (202) and an outlet (204) areformed on one side of the heat exchanger (100).
 9. The heat exchange(100) as claimed in claim 1, wherein the plurality of heat exchangechannels (104) is an I-shaped channel.
 10. The heat exchanger (100) asclaimed in claim 9, further an inlet (202) and an outlet (204) areformed on opposite sides of the heat exchanger (100) respectively.
 11. Athermal system comprising a heat exchanger (100) as claimed in any ofthe preceding claims, wherein thermal system further comprising anelectrical element (102) formed as multiple sets of cells (102A, 102B)spaced apart from each other and the electrical element (102) is placedbelow and in thermal interaction with the first plate (106).
 12. Thethermal system as claimed in claim 11, wherein the first portion (108)of the plurality of heat exchange channels (104) is adapted to be incontact with a first set of cells (102A) of the electrical element (102)and the second portion (110) of the plurality of heat exchange channels(104) is adapted to be in contact with a second set of cells (102B) ofthe electrical element (102).
 13. The thermal system as claimed in claim11, wherein a ratio between the first plate part (106A) and a secondplate part (106B) in the first portion (108) of the plurality of heatexchange channels (102) is 80%.
 14. The thermal system as claimed inclaim 11, wherein a ratio between the first plate part (106A) and asecond plate part (106B) in the second portion (110) of the plurality ofheat exchange channels (102) is 100%.